Resinous condensates and method of producing same



Patented July 9, 1940 UNITED STATES RESINOUS CONDENSATES AND METHOD OF PRODUCING SAME Karl Loos, Lancaster, Pa.

' Serial No. 128,276

No Drawing. Application February 27, 1937.

20 Claims.

The present invention relates to the production of resins suitable for casting and obtained by the condensation of an aldehyde, preferably formaldehyde, with phenol or with urea or substituted ureas, or with mixtures of phenol and a urea.

This application is a continuation-in-part of my copending application Serial No. 675,095, filed June 9, 1933. v

As is known, the transparent, translucent or opaque character of a phenol formaldehyde resinous condensation product (that is, one to which no opacifying agent has been added), and also other properties of the product, depends to a large extent upon the degree to which the water; of solution and water of reaction are expelled from the still liquid condensation mass. It is, however, frequently difiicult to dehydrate me condensate' to the desired degree because the distillation of the resin is accompanied by further 50 condensation and polymerization which make the resin more and more viscous, so that frequently it is found that the desired degree of dehydration cannot be obtained before the condensate reaches the limit of viscosity for pouring into molds.

It has been the practice to retard the arrival of the highly viscous state and thereby permit distillation for a longerlperiod of time by the use of a high vacuum which enables evaporation to take place-'atlower temperatures, but even with such expedient the temperature of distillation gradually increases and the condensate rapidlyapproaches the condition in which itcan no longer be poured. It is also known to add plasticizers, r nch-as glycerineytriacetin, etc., to the condensate during its. formation, but the known plasticizers, while they permit distilling of the resin even to the point of practically complete expulsion of the water with the obtainment of a'transparent product, undesirably aifect the properties of the resin, whether from the standpoint of resistance to water, st ength, toughness, stability, color or in other'resp ts.

I have found that a highlysatisfactory dehy dration of phenolic and urea resins can'be accomplished with the aid of a condensatitn product of acetone and formaldehyd. This condensation product, which has been named heptahydric alcohol (M. Apel and B. Tollens, Ben, 1894, 1087) appears to retard the further condensationand polymerization of the resinous reaction mass during the distillation, permitting the expulsion of the ,water of solution and subsequently of water of reaction to any desired degree while the resin remains sufliciently fluid for 55 This material thus possesses all off'the desirable plasticizing properties of known plasticizers, but is distinguished over the latter by the fact that it does not unfavorably aflect the wa ter resistance, strength, stability, machinability or other properties of the product. These improvedvproperties of the final product are probably due to the fact that the reaction retarder employed by me is composed of a substance or substances which not only are compatible with phenol and urea resins, but are in fact resinifying or of resin-forming character so that, particularly after the curing of the resin, the reaction retarder is present in the final product, not in its original condition, but'in a condensed and/or polymerized resinous state. The final product is thus most probably a single phase resinous system (leaving out of consideration any water that may be present), as contrasted with known plasticized resins which are composed of a resinous phase and a non-resinous plasticizer phase.

The reaction retarding agent according to the invention may be prepared by condensing one mol of acetone with approximately 4 to 6 mols of formaldehyde in the presence of a small amount of basic catalyst at a temperature which is preferably no higher than is required to start the exothermic reaction. Preferably, the reaction is stopped when a colorless, water-soluble alcohollike condensate is obtained. The ketone-formaldehyde condensation product so obtained combines excellently with condensation products of formaldehyde withphenol and/or a urea and yields a product which is unusually tough and easily machinable, is stable, can be given a very high polish, and can be made water-clear, cloudy, or opaque white -by controlling the degree of reaction or dehydration prior to the pouring and curing.

As already indicated, the ketone-formaldehyde condensate may be employed both with phenol- 40 formaldehyde, and with urea-formaldehyde resins and also with mixtures of such resins. The condensation in the presence of the ketone-formaldehyde reaction'product can be carried even further than has been possible hitherto,-without danger of reaching a too viscous condition. The plasticizing or polymerizationretarding character of the ketone-formaldehyde condensation products is so pronounced that the phenol-formaldehyde or .ureaefo rmaldehyde resins with which they are to be mixed can be reacted. to a I muchsgreater extent than heretofore before the distillation is begun, so that losses in raw material, especially formaldehyde, are practically completely avoided. V

The invention will be described in greater detail in the following examples but it is to be understood that the latter are presented by way of illustration onlyand that the invention is not limited thereto.

Example 1.-30 grams of acetone and 252 grams formaldehyde (37% by weight), the,,molecular proportion being 1:6, are heated gently with 6 to cc. 1N NaOH sol. in a reflux condenser. After the exothermic reaction has .subsided, theheating is continued to keep the material boiling for to 30 minutes. In another flask 300 grams phenol and 400 grams of 37% formaldehyde (by weight) are condensed under reflux with 6 grams of NaOH for 30 minutes.

Both products are then mixed together and heated under reflux for minutes. The mixture is acidified with 30 cc. of lactic acid and again heated under reflux for about to minutes until a hydrophobe resinous product precipitates out. The resinous mass is distilled to anydesired degree of dehydration, is then poured into moulds and hardened at a temperature of 60 to 80 C. In about 3 to 4 days, when the dehydration has been only partial, a hard, tough, translucent plastic is obtained which has excellent working qualities, being easily cut, drilled, turned and polished.

Example 2.300 grams phenol, 300 grams formaldehyde (37% by weight) and 3 grams NaOH are condensed for 20 minutes under reflux. There are then added 250 grams formaldehyde (37%) and 4.5 grams NaOI-ll and the mixture further condensed underv reflux for 20 min-v utes. The mass is then acidified with 30 cc. lactic acid and the condensation continued under reflux for about 30 minutes until the resin separates'from the water. Thereto a condensation product from 30 gr. acetone and 84 grams formaldehyde (37%) (the ratio being 1 mol to 2 mols) is added and the mixture distilled to a thick viscous mass which is then poured into mould and hardened at 60 to 80-C. for 4 to 5 days, whereupon a tough, translucent, high quality plastic is obtained. If an opaque white material is desired, 30 grams of urea are added at approximately 70 C. during distillation. The material then hardens in 2 to 3 days at the abovementioned temperature to an opaque, white, very strong arid easy'workable material.

/ Example 3.30 grams acetone and 252 grams of 37% formaldehyde (1 mol to 6 mols) are condensed with 10 cc. of 1N NaOI-l solution for about 30 minutes. The resulting heptahydric alcohol is then added to a condensation product obtained by boiling 200 grams phenol, 200 grams (37%) formaldehyde and 5 grams NaOH under reflux for about 30 minutes. The mixture is boiled under reflux 'for about 20 minutes, acidified with 20 cc. lactic acid and the resulting hydrophobe resin which precipitates out is distilled with 30 cc. methylphthalylethyiglycollate to substantially complete dehydration. The material is then poured into moulds and heated at 70-80" C. for 5 days. A veryilight colored, transparent, tough'and very easily machinable material is obtamed. a

Example, 4.-30 grams acetone: and 252 grams of 37% formaldehyde (1 mol to 6 mols) are cone densed with 10 cc. of 1N NapI-I solution for about 30 minutes. The resulting heptahydric alcohol is then added to a mixture of a phenol-formaldehyde resin made by boiling 300 grams phenol and 300' grams of 37% formaldehyde with 6 gramsflNaOH for 30 minutes under a reflux condenser,

and a urea-formaldehyde resin made by condens ing grams urea and 152 grams 37% formaldehyde (1 mol to 2.5 mols) with the aid of 7 cc. ammonium sulfide (saturated solution) for 30 minutes under reflux. The whole mixture is then boiled under reflux for 30.minutes, and acidified with 30 cc. lactic acid. The resulting hydrophobe resin is distilled until it is substantially dehydrated. The heavy viscous mass is poured into moulds and cured in an oven at 70 to 80 C. In 4 days a slightly translucent hornlike material is obtained which has especially high working qualities.

Example 5.30 grams acetone plus 168 grams of 37% formaldehyde (1 moi to 4 mols) are condensed with 10cc. of 1N NaOH solution. The resulting product is added to a urea-formaldehyde condensation product obtained by heating 200 grams urea, 530 grams 37% formaldehyde and 20 cc. ammonium sulflde (saturated) under reflux for 15 to 20 minutes and removing part of the water by distillation. The mixture can be distilled, without danger of becoming too viscous, to a point where almost all of the water has been expelled, and yields a more or less clear material which is stable and shows no sign of cracking long after its manufacture.

The resin produced in accordance with this example is hydrophilic in nature; that is, the mixture of the acetone and urea resins remains in the sol condition until it is poured and on hardening gelatinizes while in such condition. The products obtained according to Examples 1 to 4, on the other hand, are produced from an intermediate resinous material which is of hydrophobic nature, having been precipitated out of the aqueous solution either immediately upon acidiflcation or during the final distillation. The translucent material obtained according to Example 2 shows relatively few bubbles when magnified 200 diametersj the bubbles, which are probably droplets of water being about 1 to 2 microns in size. The material obtained according to Example 4 had the same appearance under the microscope as'that of Example 2 but showed also occasional droplets of about 40 microns in diameter. For the most part the droplets of specimens examined were about 4 microns or less in diameter.

The acetone-formaldehyde condensate can also he used with advantage in the case of hydrophilic phenolic resins made, for example, as described in Examples 1 to 3 but employing larger proportions of formaldehyde and/or sodium hydroxide. The following is a procedure illustrating the use of acetone formaldehyde condensate with a hydrophilic phenolic resin: Y

Example 6 Grams Phenol 200 Formaldehyde (37% solution) 220 NaOH I r 8' are condensed by boiling under refluxfor about hyde (molecular ratio 1:5? and 6 cc. of 1N NaOH are condensed separately for 20 minutes at the boiling temperature. The two condensates are then mixed and further condensed for 25 minutes, after which'the mixture is acidified with 30 cc. of lactic acid (85%) and distilled. The condensate remains iii the sol condition during distillation and is then poured and cooled for about flve days at -80" 0., during which it gels and hardens to a translucent, almost transparent 15 resin.

Example 7 Grams Phenol 200 Formaldehyde (37%) 212.5 NaOH 4 are condensed for 30 minutes under reflux and then mixed with grams acetone and 210 grams of 37% formaldehyde (1 mol to 6 mols) and together condensed under reflux for minutes. The condensate is acidified with 24 cc. lactic acid (85%) and heated under reflux for 15 minutes, the resin separating from the water. The hydrophobe resin is then distilled under vacuum to a a viscous mass which is poured into moulds. After 4 days curing in an oven at 70 to 80 C. a slightly translucent material is obtained which can be easily machined.

Example 8 Acetone grams 25 Formaldehyde (37%) do 210 IN NaOH solution cubic centimeters--- 5 are condensed under reflux for 30 minutes and then mixed with Grams Phenol 200 Formaldehyde (37%) 212.5 NaOH 4 and together condensed under reflux for 40 minutes. The product is then acidified with 15 cc. lactic acid and heated for 20 minutes or until separation of the resin takes place. The precipitated resin is then distilled until viscous and is 4 poured into'moulds and cured at a temperature of 70 to 80 C. An almost opaque material is obtained which has good working qualities.

Example 9 5 Grams Phenol... 200

Formaldehyde (37%) 212.5 NaOH--- 4 are condensed under reflux for 20 minutes. The 55 molecular proportion of phenol to formaldehyde is 11%. There are then added Grams Acefnne 20 Formaldehyde 112 the proportion being 1 mol to 4 'mols, and the mixture condensed for 40 minutes. The mass is then acidified with 20 cc. lactic acid and further heated under reflux for, 20 minutes until the resin 55 separates from the water. The resin is distilled under vacuum to a heavy viscous product, and is then poured into moulds and cured in an oven at 70 to 80 C. In 3to 4 days a translucent horn like material is obtained which has very good 70 working qualities, particularly in connection with turning, drillingand polishing. It will be noted that in the. above examples at least one of the'condensates (phenol-formaldehyde or acetone-formaldehyde) is produced before mixing with the materials for the other con- 1 densate; that is, the phenol (with or without urea), formaldehyde, acetone and catalyst are not mixed together from the start. 7 Such simultaneous reaction is ordinarily not satisfactory because the retarding eflect of an acetone-formaldehyde condensate cannot be realized in this way, at least not to any great extent, and it becomes diflicult to dehydrate the resinous condensate to the desired degree. The very violent reaction which takes place in such case probably causes 19 a large part of theacetone to beexpelled, as the yield is smaller than with the multi-stage process. However, when either the acetone-formaldehyde I or the phenol-formaldehyde condensate is first made separately, a satisfactorily dehydrated ll 675,095, either together with or in place of the plasticizers mentioned therein. In the production of the'urea-formaldehyde condensates above described, ammonia or amines I.

can be employed in place of ammonium sulfide; and if desired, catalysts can be dispensed with- The use of formaldehyde is preferred, but other aldehydes. such as acetaldehyde may in some instances be employed with. advantage in place 35 of part of the formaldehyde. Methyl-ethyl ketone, butyl ketone and other ketones may be used in place of acetone, but best results are generally obtained with thelatter. The lactic acid may be replaced by other organic acids hereto- 0 fore employed for neutralizing the basic catalyst in phenol-formaldehyde condensation.

Various other substitutions and changes in the proportions, temperatures, times of reaction, etc., may be resorted to by those'skilled in the art without departing from the principles of the invention.

I claim:

1. The method of producing a tough, machinable, cast resin, which comprises condensing'co phenol and formaldehyde in the ratio of 1 mol of the former'to approximately 1.1 mols to 2.2 mols of the latter in the presence of a basic condensing agent, adding thereto a considerably smaller quantity of the soluble condensation product of acetone with a much larger molecular proportion of formaldehyde, acidifying and heating the mixture until a hydrophoberesin is pre-' ci'pitated. dehydrating the'latter until a product of the desired degree of transparency or opacity on no casting and curing is obtained, and finally cast ing and curing the resinous condensate.

2. The method of producing a tough, machinable, cast resin, which comprises reacting phenol and formaldehyde and analirali metal hydroxide as,

catalyst imder such proportions that a colloidal aqueous resinous solution, is obtained, adding thereto the water-soluble condensate ofacetone with a considerably larger molecular proportion of formaldehyde produced in the presence of a basic catalyst, heating and acidifying the mixture with an organic acid, in ,any order, until a hydrophobe resin is precipitated, dehydrating the resin and then casting and curing-the same.

3. The method according to claim 1, wherein 7 in order to produce a white, opaque resin having microscopic droplets of water suspended therein, a quantity of urea is added to the reaction mixture.

4. The method according to claim 1, wherein in order to producean opaque, white resin having microscopic droplets of water suspended therein, a quantity of urea is added when the final distillation temperature hasreached about 70 C.

5. The method of producing a tough, machinable, cast resin which comprises condensing 300 grams of phenol with approximately(550 grams of 37% formaldehyde, acidifying the mass with an organic acid and continuing the condensation thereof under reflux until separation of the resin occurs, mixing the latter with the condensation product of approximately 30 grams of acetone and 84 grams of the mixture and then pouring the mass and hardening it at approximately 60 to 80 C. for.

several days.

6. The method according to claim 5, wherein, to produce a white product, approximately 30 grams of urea are added during "the final distillation.

7. The method of producing tough, machinable, cast resins, which comprises mixing (1) a water soluble condensateof acetone and formaldehyde, (2) the hydrosol obtained by condensing phenol and formaldehyde in the presence of a relatively large quantity of basic catalyst, and (3) a condensate of urea and formaldehyde, boiling the mixture and acidifying the same with an organic acid, distilling the separated resin until the desired degree of dehydration is obtained, and finally casting and'hardening the resin.

8. The method of producing a stable, transparent and machinable urea resin, which comprises condensing approximately 200 grams of urea with 530 grams of 37% formaldehyde in the presence of ammonium sulfide, mixing the condensate with the water-soluble condensate of approximately 30 grams of acetone, and 169 grams of 37% formaldehyde, produced in the presence of sodium hydroxide and distilling the mixture under vacuum until a product of the desired degree of transparency on subsequent hardening is obtained, and finally casting and curing the resinous condensate.

9. In the production of insoluble, infusible resins (if the cast type, the steps which comprise condensing aqueous formaldehyde and a member of the group consisting of phenol and urea in the presence of a basic condensing agent to produce a water-soluble condensation product, incorporating in said product a member of the group consisting of '(1) a water-soluble condensate of acetone and formaldehyde, and (2) a mixture of ace-' tone and'formaldehyde, heating anddistilling the mass to dehydrate the same to a selected degree, and finally casting and curingQthe resinous condensate.

10. In the production of resins of the cast type, the steps which eomprise condensing aqueous formaldehyde and a member of the group consisting of phenol and urea in thepresence of a basic condensing agent. to produce a water-soluble condensation product, incorporating in said product a water-soluble condensate of 'one mol of'acetone and approximately 4 to 6 mols of formaldehyde, further heating and distillingwthe mass to dehydrate the same to a selected degree, and finally casting and curing the resinous condensate.

37% formaldehyde, distilling insoluble, infusible aaoaooe 11. In the production of insoluble, infusible resins of the cast type, the steps which comprise condensing phenol and aqueous formaldehyde until a soluble condensate is obtained, incorporating in said condensate a water-soluble condensate of acetone and formaldehyde, heating and distilling the mixture to dehydrate the same to a selected degree after acidification of the mixture,

casting the still acid resin and hardening the mass to dehydrate it to a selected degree, and

thereafter casting the resin and hardening the same at atmospheric pressure at about 60-80 C.

for a number of days.

13. A process for the production of insoluble, infusible resins of the cast type comprising con-. densing 30 grams of acetone with about 252 grams of 37% formaldehyde with a relatively small amount of basic condensing agent until a watersoluble condensate is obtained; separately condensing about 300 grams of phenol with about 300 grams of 37% formaldehyde with a sufficient amount of basic condensing agent to keep the resin in solution; separately condensing about 45 grams urea and about 152 grams of 37% formaldehyde until a condensate is obtained which is still soluble, mixing and further heating the threecondensates, acidifying the mass with an organic acid, distilling the hydrophobe resin so obtained until itis substantially dehydrated, and finally casting and curing the resin.

14. The method according to claim 11, wherein a plasticizer is added after the acidification of the mixture.

15. The method of producing a stable, transparent and machinable urea resin which comprises condensing urea and aqueous formaldehyde until a still fusible, water-soluble condensate is obtained, adding thereto a water-soluble condensate of acetone and formaldehyde, distilling the mixture until so much water is expelled that upon casting and curing a transparent resin is obtained, and finally casting and curing the resin ous condensate. 4

16. The method of producing machinable cast resins, which comprises forming a condensate of aqueous formaldehyde and phenol in the presence of an amount of basic condensing agent sufficient to keep: the condensate in solution, mixing such condensate with formaldehyde and acetone, further condensing the mixture, dehydrating the resinous reaction product under acid conditions, and thencasting the still acidresin and hardening the same.

17. .The method of producing machinable resins, which comprises forming a water-sol le condensate of formaldehyde and acetone, mixing such condensate with formaldehyde and phenol,

condensing the mixture in the presence of abasic condensing agent, acidifying the condensate and further heating the mass until precipitation oc- 70 18. A cast resin comprising the reaction prodnot of formaldehyde and a member of the group consisting of phenol and'urea and having incorporated therein a condensation product of ace a -a,aoc,eoc v tone andiormaldehyde. and prepared in accord- 20. A machinable, cast resin comprising a ance with the process or claim '9.

19. A cast resin comprising the reaction product of formaldehyde and a member of the group consisting of phenol and urea and having incorporated therein a separately formed condensation product 0! 1 mol acetone and approximately 4 to 6 mole of formaldehyde and prepared in accordance with the process or claim iii.

hardened, dehydrated mixture of an acetoneiormaldehyde condensate, a phenol-formaldehyde j condensate, and a urea-formaldehyde condensate and prepared in accordance with the process 0! claim 7.

KARL L008. 

